Fluid medication delivery device

ABSTRACT

A fluid delivery device is provided for transdermal delivery of fluid medications to patients. The device can comprise a thin envelope which is applied to a patient&#39;s skin. The envelope can comprise at least one diffusion layer coupled to at least one impermeable layer such that at least one chamber can exist therebetween. Other embodiments can include internal diffusion layers, and thus can possess additional chambers, as well. The impermeable layer can comprise a top surface of the device. A valve positioned in the impermeable layer can facilitate filling the device with fluid, as well as connection of the device to external fluid sources such as an intravenous bag, pump, or other external fluid delivery system. The diffusion layer can comprise a coiled wire member to control the rate of fluid flow from the device to the patient&#39;s skin.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/663,362, filed on Sep. 16, 2003, scheduled to issue as U.S. Pat. No.7,470,266, the disclosure of which is hereby incorporated by referenceas if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to fluid delivery devices, and relatesmore particularly to a fluid medication delivery device for applicationof fluid medications to a surface area of the skin of a patient.

2. Description of the Related Art

Transdermal patches are a known means for delivering pharmaceuticalsubstances, such as fluid medications, to a patient by passing suchfluids through the patient's skin. Transdermal patches are utilized fortreatments such as hormone replacement therapy and smoking cessation.One type of transdermal patch contains an unreplenishable supply of apharmaceutical substance. The patch has a skin-contacting adhesive layerto facilitate in adhering the patch to the skin. Typically, such atransdermal patch is adhered to a suitable area of the skin for a periodof time, during which the substance is passed to the patient.

Once the pharmaceutical substance within the patch is substantiallyexhausted, the patch is removed from the skin. If more of the substancemust be delivered to the patient, a subsequent patch must be appliedand, in order to avoid irritation to the skin of the patient, often to adifferent location on the patient's skin. One drawback to using thistype of transdermal patch is that a new area of the skin must be soughtfor the application of each subsequent patch. Thus, if such patches mustbe used for an extended period of time, it may become increasinglydifficult to find an available area of the skin suitable for applicationof the patch. This difficulty becomes compounded if the skin-contactingadhesive of the patch is found to irritate the patient's skin. Anotherdrawback is that such a transdermal patch contains a fixed initialquantity (i.e., volume) of a pharmaceutical substance, and thusindividual patches are incapable of delivering large volumes of suchsubstances, such as medicinal fluids.

Another type of patch includes an injection port that permits refillingof the patch with a pharmaceutical substance using a hypodermic needle.Although such an arrangement permits reuse of the patch, the refillingprocess should be carried out by a health care worker in order toprevent injury to the patient or damage to the patch due to the use ofthe hypodermic needle. As a result, frequent visits to a health carefacility, or frequent home visits of a health care worker, are necessaryto refill the patch. Accordingly, the convenience of such an arrangementis less than ideal. Furthermore, the use of a hypodermic needle presentsa significant risk to the health care worker, as accidental pricking, orstabbing of the health care worker often accompanies to use of ahypodermic needle, or other sharp medical instrument.

Other patch-type fluid delivery arrangements allow for connection to anexternal fluid supply, but utilize complicated mechanisms for urgingdelivery of the pharmaceutical substance and/or do not provide foruniform delivery over the area of the patch. Accordingly, a need existsfor an improved transdermal patch that overcomes the limitations of theprior art.

SUMMARY OF THE INVENTION

Preferred embodiments of the present fluid delivery device provide fortransdermal delivery of fluid medications to a patient. In onearrangement, the device comprises a thin envelope, or pouch, which isattachable to a patient's skin. The envelope comprises at least onefluid semi-permeable layer coupled to at least one fluid impermeablelayer such that at least one chamber, or fluid reservoir, exists withinthe envelope.

In other arrangements, at least one additional layer may be present.Preferably, the additional layer comprises a fluid impermeable layerwith a plurality of openings therethrough. In one such arrangement, theimpermeable layer comprises a top surface of the device. A one-way valvepositioned in the impermeable layer facilitates filling the device witha fluid, as well as connecting the device to an external fluid source,such as an intravenous bag, pump, reservoir, or other external fluiddelivery system.

In one arrangement, the fluid delivery device is filled with a volume offluid and attached to the patient's skin, and thus functions as aportable source of fluid. In another arrangement, the fluid deliverydevice remains connected to an external fluid source. In such anarrangement, the device is capable of delivering a large volume of thefluid to the patient at a controlled flow rate over an extended periodof time. In addition, such an arrangement facilitates temporarydisconnection of the external fluid source without interruption of thedelivery of fluid to the patient. Preferably, diffusion of the fluidthrough the device occurs under pressure imparted to the fluid bystretching of the impermeable layer(s) when the device is filled withthe fluid and/or pressure supplied to the device by an external fluidsource.

One aspect of the present invention involves a fluid medication deliverydevice including a fluid impermeable layer and a fluid semi-permeablelayer. The semi-permeable layer and the impermeable layer cooperate todefine a space therebetween. The space defines a fluid reservoir of thedelivery device. The semi-permeable layer and the impermeable layer havea continuous seal therebetween to define a periphery of the fluidreservoir. A fluid inlet communicates with the fluid reservoir andcomprises a valve configured to permit fluid entry into the fluidreservoir. In one arrangement, the valve is a one-way type valve thatprevents the exiting of fluid from the reservoir through the inlet. Thefluid inlet is adapted to permit connection to a supply of fluid. Afluid is diffusable across the semi-permeable layer, desirably, inresponse to either one of a pressure imparted on the fluid by the layersof the delivery device or a pressure imparted by an external source offluid.

A further aspect of the present invention involves a fluid medicationdelivery device including a fluid impermeable pouch having first andsecond opposing walls. The first wall and the second wall define a spacetherebetween. The space defines a fluid reservoir of the deliverydevice. The second wall includes a plurality of openings therethroughdefining a diffusion area of the delivery device. A fluid inletcommunicates with the fluid reservoir and comprises a valve configuredto permit fluid entry into the fluid reservoir. The fluid inlet isadapted to permit connection to a supply of fluid. A fluidsemi-permeable layer covers at least the diffusion area of the deliverydevice and is configured such that fluid within the fluid reservoir mustpass through the semi-permeable layer before exiting the deliverydevice.

Yet another aspect of the present invention involves a system fordelivering a medicinal fluid to a dermal area of a patient. The systemincludes a delivery device having a fluid impermeable layer and a fluidsemi-permeable layer cooperating to define a space therebetween. Thespace defines a fluid reservoir of the delivery device. A fluid inletcommunicates with the fluid reservoir. A pump is configured to apply apressure to a medicinal fluid and is connectable to the fluid inlet tosupply a flow of the medicinal fluid to the fluid reservoir throughout adelivery cycle. When the infusion pump is connected to the fluid inlet,the medicinal fluid within the reservoir diffuses across thesemi-permeable layer in response to the pressure applied by the infusionpump.

Still another aspect of the present invention involves a fluidmedication delivery device including a fluid impermeable pouch havingfirst and second opposing walls. The first wall and the second walldefine a space therebetween. The space defines a fluid reservoir of thedelivery device. The second wall includes a plurality of openingstherethrough defining a diffusion area of the delivery device. A coiledwire member covers at least the diffusion area of the delivery deviceand is constructed of a plurality of adjacent wire sections defining aplurality of gaps therebetween. The coiled wire member is configuredsuch that fluid within the fluid reservoir must pass through the coiledwire member before exiting the delivery device.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention are described with reference to drawings of several preferredembodiments, which are intended to illustrate, but not to limit, thepresent invention. The drawings include twenty-two figures.

FIG. 1 is a perspective, partial cutaway view of a fluid deliverydevice. The fluid delivery device of FIG. 1 includes a fluid impermeablelayer and a fluid semi-permeable layer joined by a circumferential sealand defining a fluid reservoir therebetween. A fluid inlet permits entryof fluid into the fluid reservoir.

FIG. 2 is a top view of the fluid delivery device of FIG. 1.

FIG. 3 is a side elevation view of the fluid delivery device of FIG. 1.

FIG. 4 is a cross-sectional view of the fluid delivery device of FIG. 1,taken along line 4-4 of FIG. 2.

FIG. 5 is a perspective view of one exemplary environment of use of thefluid delivery device of FIG. 1, wherein the device is utilized todeliver fluid to the forearm of a patient.

FIG. 6 is a cross-sectional view of the exemplary use environment ofFIG. 5, illustrating a volume of fluid contained within the fluidreservoir of the delivery device.

FIG. 7 is a perspective, partial cutaway view of another embodiment of afluid delivery device. The device of FIG. 7 includes upper and lowerfluid impermeable layers. The lower impermeable layer includes aplurality of openings configured to allow fluid to pass therethrough. Afluid semi-permeable layer is positioned between the upper and lowerlayers and is configured to cover the plurality of openings.

FIG. 8 is a cross-sectional view of the fluid delivery deviceillustrated in FIG. 7, taken along line 8-8 of FIG. 7.

FIG. 9 is a perspective, partial cutaway view of yet another embodimentof a fluid delivery device. The device of FIG. 9 includes upper andlower fluid impermeable layers, with the lower layer including aplurality of openings configured to allow fluid to pass therethrough. Afluid semi-permeable layer is positioned adjacent an external surface ofthe lower layer and is configured to cover the plurality of openings.

FIG. 10 is a cross-sectional view of the fluid delivery deviceillustrated in FIG. 9, taken along line 10-10 of FIG. 9.

FIG. 11 is a top view of an embodiment of a fluid delivery device havinga dog-bone outer shape.

FIG. 12 is a top view of an embodiment of a fluid delivery device havingan oval outer shape.

FIG. 13 is a top view of an embodiment of a fluid delivery device havinga rectangular outer shape.

FIG. 14 is a top view of an embodiment of a fluid delivery device havinga square outer shape.

FIG. 15 is a top view of an embodiment of a fluid delivery device havinga triangular outer shape.

FIG. 16 is a top view of a fluid delivery device having a top layerpartially cutaway to show a coiled wire diffusion layer of the device.

FIG. 17 is a side, cross-sectional view of the delivery device of FIG.16, taken along line 17-17 of FIG. 16.

FIG. 18 is a top view of a fluid delivery device having a plurality oflinear seams dividing the interior reservoir into a plurality ofinterconnected regions, or flow channels.

FIG. 19 is a side, cross-sectional view of the delivery device of FIG.18, taken along the line 19-19.

FIG. 20 is a top view of a modification of the fluid delivery device ofFIG. 18, wherein the seams radiate outwardly from a fluid inletpositioned proximate an edge of the device.

FIG. 21 is a top view of another modification of the fluid deliverydevice of FIG. 18, wherein a single seam includes a series of linearportions serially connected with one another to divide the internalreservoir into essentially two portions.

FIG. 22 is a top view of yet another modification of the fluid deliverydevice of FIG. 18, wherein a plurality of seams radiate outwardly from acenter point of the device. A fluid inlet may be located proximate anedge of the device, as shown in solid line, or it may be locatedapproximately in the center of the device, as shown in phantom.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Although certain preferred embodiments and examples are disclosed below,it will be understood by those skilled in the art that the inventionextends beyond the specifically disclosed embodiments to alternativeembodiments and/or uses of the invention and obvious modifications andequivalents thereof. Thus, it is intended that the scope of theinvention herein disclosed should not be limited by the particularembodiments described below.

FIGS. 1 through 4 illustrate a preferred embodiment of a fluid deliverydevice, generally referred to by the reference numeral 10. The fluiddelivery device 10 includes a thin, circular pouch, or envelope 12,which is adapted for placement on the skin of a patient. Preferably, aninlet valve assembly 14 permits fluid communication with an interiorspace of the envelope 12.

As illustrated in FIGS. 1 through 4, preferably, the envelope 12 isconstructed of a fluid impermeable sheet 18, and a fluid semi-permeablesheet, or diffusion sheet 20, which permits fluid to pass therethroughat a substantially uniform rate. In the illustrated embodiment, outeredge portions of the impermeable sheet 18 and the diffusion sheet 20 aresecured to one another by a peripheral seal 16, such that asubstantially fluid tight interior chamber 22 is formed therebetween.Thus, the peripheral seal 16 defines a periphery of the interior chamber22, or a fluid reservoir of the delivery device 10. The seal 16 may beconstructed in any suitable manner. For example, the seal 16 may becreated by heat bonding, chemical bonding, or RF welding, for example,but without limitation. In addition, one or more additional componentsmay be utilized to form the seal 16, such as an overlapping orreinforcing member, for example. Other methods of creating asubstantially fluid tight interior chamber apparent to one of skill inthe art may also be used.

An outwardly facing surface of the impermeable sheet 18 defines a topsurface of the device 10, which preferably does not contact thepatient's skin. An outwardly facing surface of the diffusion sheet 20defines a bottom, contact surface of the device 10, which is placed onthe patient's skin during operation of the device 10. In such anarrangement, adhesive, preferably in the form of an adhesive layer, maybe present on the exposed portion of a lower surface of the diffusionsheet 20 to assist in securing the device 10 to the skin of the patient.The adhesive may be provided on the entire external surface of thediffusion sheet 20 or on only a portion of the external surface, such asa peripheral portion, for example. Although not specificallyillustrated, an addition, removable protective sheet may be provided toprotect the adhesive, and maintain sterility, before use of the device10. In addition, such a layer may prevent fluid from exiting thereservoir through the diffusion sheet 20, when attached to the device10, to permit the device 10 to be prefilled with a fluid.

In alternative arrangements, the impermeable sheet 18 and the diffusionsheet 20 may not necessarily be of the same size and shape. In one sucharrangement, the upper, impermeable sheet 18, may be larger than thelower, diffusion sheet 20 and, thus, a portion of the impermeable sheet18 may contact the skin of the patient. Alternatively, other suitablemeans for securing the device 10 to the skin of the patient may beutilized, such as another layer, an external wrapping, for example,alone or in combination with adhesive provided on the device 10, as isdescribed in greater detail below with reference to FIGS. 5 and 6.

Preferably, the diffusion sheet 20 is at least partially constructedfrom a biocompatible material suitable for exposure to the types ofmedicinal fluids contemplated, as will be readily appreciated by one ofskill in the art. In the embodiment illustrated in FIGS. 1 through 4,the diffusion sheet 20 is constructed from a semi-permeable membraneconfigured to control the rate of fluid flow therethrough, as well asprovide for uniform distribution of the fluid.

The semi-permeable membrane, or porous membrane, includes a plurality ofpores, or tortuous passages extending therethrough. Preferably, each ofthe pores have a diameter of no more than about 0.25 μm. As will beappreciated by one of skill in the art, it is not necessary that thepores be circular in cross-sectional shape. Accordingly, the recitationof the pores having a diameter is not intended to be a limitation on thepresent invention. Rather, it is assumed that the cross-sectional shapecan be assumed to be circular for the purpose of describing passages ofsuch a size.

Suitable materials from which the semi-permeable membrane may beconstructed include, without limitation, polyethylene, polysulfone,polyethersulfone, polyvinylidene, diflouride, polycarbonate, nylon, highdensity polyethylene, polytetrafluoroethylene, or other similarmaterials. Other materials that may comprise the diffusion sheet 20include, but are not limited to, suture materials, surface coated and/ortreated metals such as stainless steel, and ferrous/nonferrous alloys.In other embodiments, however, the diffusion sheet 20 may besupplemented or replaced by a perforated impermeable sheet, coiledspring, coiled wire/cord, or another similar device for controlling therate and distribution of fluid flowing from the interior chamber 22 tothe patient's skin, as is described in greater detail below.

As illustrated in FIGS. 1 through 3, preferably the valve 14 iscentrally positioned on the impermeable sheet 18. In other embodiments,the valve 14 may be positioned in other locations on the impermeablesheet 18 or other locations of the device 10 that permit communicationwith the interior chamber 22. The illustrated valve 14 defines an inletpassage 23 (FIG. 3) that permits fluid communication from the outsideenvironment to the interior chamber 22. Preferably, the valve 14 is a“one-way” valve assembly. That is, the valve 14 allows fluidcommunication from the outside environment to the interior chamber 22,while substantially preventing fluid within the interior chamber 22 fromexiting through the valve 14. Any suitable construction may be used toprovide the “one-way” function of the valve 14, as will be appreciatedby one of skill in the art.

Desirably, the valve 14 is adapted to receive a coupler, such as a luerconnector, to permit the coupling of an external fluid supply source, orpressure source, to the device 10. In addition, other suitable types ofconnection assemblies may also be used. Advantageously, the “one-way”nature of the valve 14 permits coupling, and uncoupling, of an externaldevice to the delivery device 10 without loss of fluid from the interiorchamber 22. Furthermore, a cap (not shown) may be provided to cover andprotect the valve 14 from damage or contamination.

The illustrated fluid delivery device 10 is particularly well-suited forthe continuous delivery of fluid medication(s), such as antibiotics,local anesthetics, drug “cocktails”, and/or other fluid substances, to asurface area of the skin of a patient. The surface area may be of a widevariety of shapes and sizes and may consist of wound sites, burns, skingrafts or other such treatment areas of the skin surface.

FIGS. 5 and 6 illustrate one such exemplary use environment wherein thefluid delivery device 10 is utilized to deliver a fluid 108 to the skinof a forearm 102 of a patient. Although not shown in FIGS. 5 and 6, asterile dressing, such as a bandage or elastic wrap, may be used to fixthe device 10 in position on the forearm 102. The sterile dressing mayalso be used to apply a force to the device 10 in order to pressurizethe fluid 108 therein. The sterile dressing may be utilized topressurize the fluid 108 in addition to pressure supplied by an externalsource of fluid (not shown) and/or the device 10 itself, or the steriledressing may be the only means of pressurizing the fluid.

In the illustrated arrangement, a tube 104 is connected to the valve 14of the fluid delivery device 10. It is contemplated that the valve 14and the tube 104 place the device 10 in fluid communication with anexternal fluid source (not shown), such as an intravenous bag, pump,reservoir, or other external fluid delivery system. Once the fluiddelivery device 10 is filled with a volume of the fluid 108, as shown inFIG. 6, the tube 104 may be disconnected from the valve 14. The one-wayfeature of the valve 14 ensures that the fluid does not leak from theinterior chamber 22. With the tube 104 disconnected, the fluid deliverydevice 10 functions as a portable source of the fluid 108 to thepatient. However, as will be appreciated by one of skill in the art, thevalve 14 may also be a two-way valve, which permits fluid 108 to bothenter and exit the reservoir through the valve 14.

In such an arrangement, when the interior chamber 22 of the device 10 isfilled with the fluid 108, pressure is imparted to the fluid 108preferably by stretching of the impermeable sheet 18 of the device 10.This pressure causes the fluid 108 to diffuse from the interior chamber22 to the forearm 102. However, it is not necessary that the upper andlower sheets 18, 20 be capable of stretching. The fluid 108 maynonetheless diffuse through the diffusion sheet 20 without pressureimparted by the impermeable sheet 18 or diffusion sheet 20. Desirably,the diffusion sheet 20 influences the flow rate of the fluid 108 anduniformly distributes the fluid 108 on the skin. Specifically, in apreferred arrangement, the pore size of the diffusion sheet 20determines the flow rate of the fluid 108 from the device 10.

In an alternative arrangement, the tube 104 (and the external fluidsource) may remain connected to the one-way valve 14 so that the device10 continuously delivers the fluid 108 to the patient at a controlledflow rate. With this method, preferably diffusion of the fluid 108through the device 10 occurs under a combination of pressure imparted tothe fluid 108 by the internal system pressure of the delivery device 10,as discussed above, and pressure supplied by the external fluid source.The delivery of fluid 108 may continue until the external supply offluid is exhausted. In other words, the external fluid supply determinesthe duration of the delivery cycle. In fact, due to the internalreservoir (e.g., the interior chamber 22) of the delivery device 10, theexternal fluid supply may be replaced once empty while delivery of thefluid 108 continues as a result of the internal system pressure of thedevice 10 and the fluid 108 remaining within the reservoir 22. Thus, theexternal fluid supply may be replenished, without interrupting deliveryof fluid 108 to the patient.

In use, preferably, the protective sheet, if provided, is removed fromthe device 10 and the device 10 is applied to a desired area of the skinof the patient, such as the forearm 102, for example. The device 10 isconnected to the external source of fluid by connecting the tube 104 tothe valve 14 of the fluid delivery device 10. The reservoir 22 of thedevice 108 is filled with fluid 108 from the external fluid source. Oncethe reservoir 22 is filled to a sufficient level, fluid begins todiffuse across the diffusion sheet 20 and through the skin of thepatient. If desired, an external wrapping, such as a sterile bandage ordressing, may be applied over the fluid delivery device 10 to protectthe device 10, maintain sterile conditions, and/or assist in diffusionof the fluid 108.

When the external source of fluid has been substantially depleted, thetube 104 may be disconnected from the device 10 and the externalwrapping (if any) and device 10 may be removed from the patient.Alternatively, the tube 104 may be disconnected from the device 10 andanother external fluid source may be connected to the device 10. Thus,the external fluid source may be renewed without removing the device 10from the patient. Furthermore, if fluid 108 is still present within thereservoir 22 when the external fluid source is disconnected, areplenished fluid source may be connected to the device 10 and begindelivering fluid to the delivery device 10. Thus, fluid delivery to thepatient may proceed uninterrupted during replenishment of the externalfluid source.

FIGS. 7 and 8 illustrate a modification of the delivery device 10 ofFIGS. 1-6, and is generally referred to by the reference numeral 30.Like components are designated with like reference numerals throughoutthe figures. The delivery device 30 is also adapted for placement on theskin of a patient and, preferably, is substantially similar to the fluiddelivery device 10. However, the delivery device 30 of FIGS. 7 and 8 iscomprised of more than two layers. Specifically, the device 30 includesan impermeable sheet 18, a fluid semi-permeable diffusion sheet 20 and alower impermeable sheet 32. Similar to the device 10 described above,the sheets 18, 20, 32 are attached to one another by a peripheral seal33 such that the diffusion sheet 20 defines a first chamber 34 and asecond chamber 36 between the impermeable sheets 18, 32, respectively.The first and second chambers 34, 36, collectively, define a fluidreservoir of the device 30. In an alternative arrangement, the diffusionsheet 20 and the lower impermeable sheet 32 may be bonded together,thereby eliminating the second chamber 36. The sheets 20, 32 thus form acompound sheet that, preferably, controls the flow rate and distributionof fluid passing from the first chamber 34 to the skin of the patient.

In the illustrated embodiment, the diffusion sheet 20 is of asubstantially similar size and shape as the upper and lower sheets 18,32. However, in an alternative arrangement, the diffusion sheet 20 maybe smaller than either of the upper and lower sheets 18, 32 and may besecured to the lower sheet 32 separately from the peripheral seal 33.For example, the diffusion sheet 20 may cover only a portion of thelower, impermeable sheet 32 and may be secured to the sheet 32 by a sealseparate from, but similar to, the peripheral seal 33. In such anarrangement, preferably, openings in the lower sheet 32 are providedonly within the area covered by the diffusion sheet 20. That is,desirably, the device 30 is arranged such that fluid within thereservoir 34 must pass through the diffusion sheet 20 before exiting thedevice 30 so that the flow rate of the fluid remains substantiallyuniform.

A valve 14 is positioned on the impermeable sheet 18 and facilitatesfluid communication from the outside environment to the first chamber34. The valve 14 preferably is a one-way valve, which is adapted toreceive a coupler, such as a luer connector. The one-way valve 14facilitates filling the first chamber 34 with a fluid and/or connectingthe first chamber 34 to an external fluid source (where employed).

The lower impermeable sheet 32 defines at least a portion of a bottomsurface of the device 30, which is placed in contact with the patient'sskin during use of the device 30. As illustrated in FIG. 7, preferablythe lower impermeable sheet 32 has a plurality of passages 35 that allowpassage of the fluid from the second chamber 36 to the patient's skin.Preferably, the passages comprise small diameter, circular holes.Desirably, the holes 35 each have a diameter ranging between about 0.25μm and about 0.254 mm. Furthermore, preferably, the holes 35 aredistributed substantially evenly over the lower impermeable sheet 32, ora substantial portion thereof. The region of the lower impermeable sheet32 that includes the holes 35 generally defines a diffusion section ofthe delivery device 30. That is, fluid within the device 30 is deliveredin a substantially uniform manner over the diffusion section.

Preferably, use of the fluid delivery device 30 is substantially similarto the operation of the fluid delivery device 10 of FIGS. 1-6. However,fluid entering the device 30 via the valve 14 enters the first chamber34 and then is diffused into the second chamber 36, through thediffusion sheet 20, before passing through the openings 35 of the lowerimpermeable sheet 32 to the patient's skin. In operation, the firstchamber 34 is filled with a volume of fluid and the diffusion sheet 20allows the fluid to pass from the first chamber 34 into the secondchamber 36 at a controlled flow rate. The plurality of small holes 35 inthe lower impermeable sheet 32 uniformly distributes the fluid as itpasses from the second chamber 36 to the skin of the patient.

As discussed above with reference to FIGS. 5 and 6, it is contemplatedthat a tube may be connected to the valve 14 of the device 30, therebyplacing the first chamber 34 in fluid communication with an externalfluid source (not shown), such as an intravenous bag, pump, reservoir,or other external fluid delivery system. In one arrangement, the fluiddelivery device 30 may be filled with a volume of fluid and then thetube disconnected from the valve 14. Upon disconnection of the tube, thefluid delivery device 30 functions as a portable source of the fluid tothe patient. It will be appreciated that when the first chamber 34 ofthe device 30 is filled with the fluid, desirably, pressure is impartedto the fluid by stretching of the impermeable sheet 18 of the device 30and/or by an external dressing, as described above. This pressure causesthe fluid to diffuse from the first chamber 34 to the second chamber 36at a controlled rate and then to flow to the patient's skin through theholes 35.

Alternatively, the tube (and the external fluid source) may remainconnected to the valve 14 so that the device 30 continuously deliversthe fluid to the patient at a controlled flow rate. Thus, preferably,diffusion of the fluid through the device 30 occurs under a combinationof pressure imparted to the fluid by stretching of the impermeable sheet18 and pressure supplied by the external fluid source.

FIGS. 9 and 10 illustrate another embodiment of a fluid delivery device40, which is adapted for placement on the skin of a patient. The fluiddelivery device 40 shown in FIGS. 9 and 10 is substantially similar tothe fluid delivery device 10, illustrated in FIGS. 7 and 8, with theexception that the lower impermeable sheet 42 is positioned between thediffusion sheet 20 and the upper impermeable sheet 18. As in theprevious embodiments, preferably, the impermeable sheets 18, 42 and thediffusion sheet 20 are attached to one another by a peripheral seal 43such that the lower impermeable sheet 42 defines a first chamber 44 anda second chamber 46 between the impermeable sheet 18 and the diffusionsheet 20, respectively. The impermeable sheets 18, 42 may be made ofplastic or other similar material, as described above.

Preferably, a valve 14 is positioned on the impermeable sheet 18 andprovides fluid communication from the outside environment to the firstchamber 44. The valve 14 is configured to allow fluid to enter the firstchamber 44 without fluid leaking back to the outside environment. Thevalve 14 preferably is adapted to receive a coupler, such as a luerconnector. The valve 14 facilitates filling the first chamber 44 with afluid and/or connecting the first chamber 44 to an external fluid source(where employed).

As illustrated in FIG. 9, the lower impermeable sheet 42 (intermediatelayer) includes a plurality of small diameter holes 45, which uniformlydistribute fluid flow from the first chamber 44 to the second chamber46. Desirably, each of the holes 45 has a diameter of between about 0.25μm and about 0.254 mm. Fluid in the second chamber 46 then passesthrough the diffusion sheet 20 to the patient's skin. As discussed withreference to FIGS. 1-4, preferably, the diffusion sheet 20 is comprisedof a semi-permeable membrane which controls the rate of flow to theskin, as well as uniformly distributing the fluid passing through thediffusion sheet 20. The diffusion sheet 20 comprises a bottom surface,which defines at least a portion of the skin contact surface of thedevice 40. In another embodiment, the sheets 20, 42 are bonded together,thereby eliminating the second chamber 46. In this embodiment, thesheets 20, 42 comprise a compound sheet that controls the flow rate anddistribution of fluid passing from the first chamber 44 to the patient'sskin.

It will be appreciated that the fluid delivery device 40 may be utilizedfor continuous delivery of fluid medication(s), such as antibiotics,local anesthetics, drug “cocktails”, and/or other fluid substances, to asurface area such as a wound site or treatment area on a patient's skin.Operation of the fluid delivery device 40 is substantially similar tothe operation of the fluid delivery device 30, described above. Inoperation, fluid entering the device 40 via the valve 14 enters thefirst chamber 44 and then is distributed into the second chamber 46(where employed) before being controllably passed on to the patient'sskin. When the device 40 is placed on the skin and the first chamber 44is filled with a volume of fluid, the holes 45 in the lower impermeablesheet 42 uniformly the fluid from the first chamber 44 into the secondchamber 46. The diffusion sheet 20 then allows the fluid to pass at acontrolled flow rate from the second chamber 46 to the skin of thepatient.

As discussed above with reference to FIGS. 5 and 6, it is contemplatedthat a tube may be connected to the valve 14 of the device 40, therebyplacing first chamber 44 in fluid communication with an external fluidsource (not shown), such as an intravenous bag, pump, reservoir, orother external fluid delivery system. In one embodiment, the fluiddelivery device 40 may be filled with a volume of fluid and then thetube disconnected from the valve 14. The fluid delivery device 40 thenfunctions as a portable source of the fluid to the patient. It will beappreciated that when the first chamber 44 of the device 40 is filledwith the fluid, pressure is imparted to the fluid by stretching of theimpermeable sheet 18 and/or by an external wrap, or dressing, asdescribed above. This pressure causes the fluid to flow from the firstchamber 44 to the second chamber 46 and then diffuses controllably tothe patient's skin.

Alternatively, the tube (and the external fluid source) may remainconnected to the valve 14 so that the device 40 continuously deliversthe fluid to the patient at a controlled flow rate. With the tubeconnected to the valve 14, diffusion of the fluid through the device 40desirably occurs under a combination of pressure imparted to the fluidby stretching of the impermeable sheet 18 and pressure supplied by theexternal fluid source.

It will be appreciated that depending on the particular surface arearequiring treatment, the fluid delivery devices 10, 30 and 40 mayadvantageously be configured with a variety of shapes and sizes, as wellas combinations thereof. FIGS. 11 through 15 illustrate severalembodiments of fluid delivery devices having advantageous shapes andsizes. It is to be noted, however, that other shapes and sizes thanthose shown herein, as well as combinations of these and other shapesand sizes providing still more complex shapes, are contemplated and thusfall within the scope of the present invention.

FIG. 11 illustrates an embodiment of a fluid delivery device 50comprising an envelope 51 and a valve 14. The envelope 51 comprises afirst circular portion 52 and a second circular portion 54interconnected by a rectangular bridge portion 56. The valve 14 is ofthe “one-way” variety and is adapted to receive a luer connector. It iscontemplated that the device 50 may comprise any number and/orcombination of the sheets and the interior chambers discussed above withreference to FIGS. 1 through 10. As with the devices 10, 30, 40, thesheets comprising the fluid delivery device 50 are attached to oneanother by a peripheral seal 58. Operation of the fluid delivery device50 is substantially similar to the operation of the devices 10, 30 or40.

FIG. 12 illustrates an embodiment of a fluid delivery device 60comprising an oval envelope 62 including a one-way valve 14. It iscontemplated that the device 60 may comprise any number and/orcombination of the sheets discussed herein, and are sealed to oneanother by a peripheral bond 64. Depending on the sheets utilized withinthe oval envelope 62, operation of the fluid delivery device 60 issubstantially similar to the operation of the devices 10, 30 or 40.

Another embodiment of a fluid delivery device 70 is illustrated in FIG.13. As shown, the fluid delivery device 70 comprises a rectangularenvelope 72 having a valve 14. It is contemplated that the rectangularenvelope 72 may comprise any number and/or combination of the sheets andinterior chambers discussed herein. The sheets comprising therectangular envelope 72 are attached to one another by a seal 74.Depending on the particular sheets comprising the rectangular envelope72, operation of the fluid delivery device 70 is substantially similarto the operation of the devices 10, 30 or 40.

It is contemplated that the dimensions of the rectangular envelope 72may be changed so as to form other envelopes having differentrectangular shapes and sizes, including but not limited to square-shapedenvelopes. One embodiment of a fluid delivery device 80 having a squareenvelope 82 is shown in FIG. 14. As with the rectangular envelope 72illustrated in FIG. 13, the square envelope 82 includes a one-way valve14 positioned generally in the center of the envelope 72. The squareenvelope 82 may comprise any number and/or combination of the sheetsdiscussed herein. The sheets are sealed to one another by a peripheralseal 84. Depending on the particular sheets comprising the squareenvelope 82, operation of the fluid delivery device 80 is substantiallysimilar to the operation of the device 10, 30 or 40.

FIG. 15 illustrates another embodiment of a fluid delivery device 90comprising a triangular envelope 92. The triangular envelope 92 includesa valve 14, which is adapted to receive a luer connector. As with thedevices discussed above, the triangular envelope 92 may comprise anynumber and/or combination of the sheets discussed herein. The sheetscomprising the triangular envelope 92 are attached to one another by aperipheral seal 94. Depending on the particular sheets utilized withinthe triangular envelope 92, operation of the fluid delivery device 90 issubstantially identical to the operation of the devices 10, 30 or 40.

FIGS. 16 and 17 illustrate another embodiment of a fluid deliverydevice, generally referred to by the reference numeral 100. The fluiddelivery device 100, preferably, is substantially similar to the device30 of FIGS. 7 and 8, with the exception that the diffusion sheet 20 (ofthe device 30) is replaced by a coiled wire member 102. Desirably, inoperation, the coiled wire member 102 permits fluid to pass through themember 102 at a controlled rate and in a substantially uniform mannerover the area of the coiled wire member 102.

As in the previous embodiments, the fluid delivery device 100, includesan upper layer 104 and a lower layer 106. Preferably, the upper andlower layers 104, 106 are joined by a peripheral seal 108. The coiledwire member 102 is positioned within the space, or fluid reservoir 110,between the upper layer 104 and the lower layer 106. The coiled wiremember 102 may vary in overall size, but preferably covers a significantportion of the lower layer 106. More preferably, the coiled wire member102 covers substantially all of the lower layer 106 such that asubstantial portion of the fluid within the reservoir 110, andpreferably substantially all of the fluid within the reservoir 110,passes through the coiled wire member 102 before exiting the device 100.

In the illustrated arrangement, the coiled wire member 102 isconstructed from a singular wire element 112 manipulated to expand froma center point C, in a substantially constantly increasing radius, intoa coiled shape. Accordingly, a substantially constant gap 114 is definedbetween adjacent portions of the wire 112. Such an arrangementfacilitates the controlled rate and uniform diffusion function of themember 102. In other arrangements, however, the coiled wire member 102may be constructed from a plurality of individual rings, incrementallyincreasing in diameter and secured to one another. Other arrangementsmay utilize a singular wire element formed into shapes other thancircular, but preferably defining a substantially constant gap betweenadjacent portions of the wire. Furthermore, the wire element 112 mayassume a variety of cross-sectional shapes including, but not limitedto, circular or rectangular. In one arrangement, the wire element 112may be formed such that the adjacent coils are in contact along at leasta portion of the coiled wire member 102. In such an arrangement, fluidmay pass through small gaps in the adjacent coils or as a result of thecoiled wire member 102 stretching in response to fluid pressure.

Preferably, as illustrated in FIG. 17, the coiled wire member 102 issubstantially planar so as to facilitate adhesion to one or both of thelayers 104, 106, if desired. In a preferred arrangement, at least aportion of the coiled wire member 102 is secured to the lower layer 106.The coiled wire member 102 may be secured to the lower layer 106 alongthe entire length of the lower surface of the wire element 112.Alternatively, the member 102 may be secured to the lower layer 106 atone or more distinct points or regions of the wire element 112, such asalong an outer circumference of the member 102 or central portion of themember 102, for example. Advantageously, with such an arrangement, thecoiled wire member 102 may be capable of expansion and retraction toalter the size of the gap 114 between adjacent portions of the wireelement 112 in response to pressure exerted by fluid within the device100.

Any suitable method may be used to secured the coiled wire member 102 toone or more of the layers 104, 106 including, but not limited to,chemical or thermal bonding. In the illustrated embodiment, the coiledwire member 102 covers only a portion of the lower layer 106 of thefluid delivery device 100. However, in an alternative embodiment, thecoiled wire member 102 may cover substantially the entire lower layer106 and, optionally, may be secured within the peripheral seal 108between the upper and lower layers 104, 106.

Preferably, the lower layer 106 includes a plurality of openings 116 topermit fluid to pass out of the fluid reservoir 110. Collectively, theopenings 116 define a fluid diffusion area of the delivery device 100.Desirably, the openings 116 cover a substantially equivalent, althoughslightly smaller, area of the lower layer 106 than an area covered bythe coiled wire member 102. Therefore, fluid within the fluid reservoir110 passes through the gaps 114 of the coiled wire member 102 beforepassing through the openings 116, and exiting the device 100.

Preferably, similar to the embodiments described above, the fluiddelivery device 100 employs an adhesive in the form of an adhesive layeron an external surface of the lower layer 106 to permit the device 100to be securably positioned on the skin of a patient. The adhesive maycover the entire external surface of the lower layer 106, or only aportion thereof. In one arrangement, the adhesive is provided only on aperiphery of the external surface of the lower layer 106. A wrap orbandage may also be used, alone or in complement with an adhesive, tosecure the device 100 in a desired position on the skin of a patient. Inaddition, the fluid delivery device 100 is provided with a fluid inlet14 to permit fluid to be introduced into the fluid reservoir 110 and,desirably, to permit connection of the device 100 to an external sourceof fluid, as described in relation to the embodiments above.

With reference to FIGS. 18 and 19, another embodiment of a fluiddelivery device, referred to generally by the reference numeral 120, isillustrated. The fluid delivery device 120 is similar to theabove-described embodiments in that the device 120 defines a fluidreservoir 122 between an upper layer 124 and a lower layer 126 joined bya peripheral seal 128. Preferably, the upper layer 124 comprises a fluidimpermeable sheet and the lower layer 126 comprises a fluidsemi-permeable sheet. Desirably, the fluid semi-permeable sheet isconfigured to permit fluid to pass therethrough at a controlled,substantially uniform rate. However, the device 120 may alternatively beconstructed from more than two layers, as described above in relation tothe device 30 of FIGS. 7 and 8, the device 40 of FIGS. 9 and 10, and thedevice 100 of FIGS. 16 and 17. In addition, the delivery device 120preferably includes an inlet 14 to permit fluid to be introduced intothe reservoir 122 and to permit the device 120 to be connected to anexternal fluid source.

The fluid delivery device 120 differs from the above-describedembodiments primarily in that the fluid reservoir 122 of the device 120is segmented into a plurality of interconnected regions 122 a-h. In theillustrated embodiment, the regions 122 a-h are defined by a pluralityof seams 130 created by securing the upper layer 124 to the lower layer126, preferably along a linear or curvilinear path. For efficiency inthe manufacturing process, it is preferred to form the seams 130simultaneously with the formation of the peripheral seal 128. However,the seams 130 and peripheral seal 128 may also be created in separateprocess steps. In addition, other suitable methods of definingindividual regions within the reservoir 122 may also be used.

Collectively, the regions 122 a-h define a plurality of “flow channels”within the interior chamber, or reservoir 122. It is contemplated thatthe flow channels are sized and positioned within the device 120 so asto provide a substantially uniform distribution of the fluid to thelower, semi-permeable layer 126. Desirably, the flow channels divide thefluid within the device 120 such that the pressure exerted on the fluid,by the device 120 itself or an external source of pressure, is moreevenly distributed to the fluid. As a result, the diffusion of fluid ismore uniform over the diffusion area defined by the device 120.Moreover, it is contemplated that the size and/or shape of the flowchannels is further influenced by the particular type of fluid which isintended to be diffused through the fluid delivery device 120, and/orthe overall shape of the device 120. For example, in the device 120 ofFIGS. 18 and 19, the device 120 is of a circular shape and the seams 130are linear, and arranged substantially parallel to one another.

FIGS. 20-22 illustrate additional fluid delivery devices, 140, 150 and160, which are substantially similar to the device 120 of FIGS. 18 and19. In the circular device 140 of FIG. 20, a fluid inlet 14 ispositioned near an edge of the device 140 and the seams 130 radiateoutwardly from approximately a center point of the inlet. Thus, fluidintroduced into the device 140 is separated into the flow channelscreated by the plurality of seams 130, wherein the pressure exerted ontothe fluid by the device 120, or an external pressure source, is moreevenly distributed to the fluid and results in a more uniform deliveryof the fluid.

FIG. 21 illustrates a circular fluid delivery device 150 having a singleseam 130 formed into a meandering shape to define a plurality ofsubstantially parallel sections of the seam 130, which are connected toone another in series. A fluid inlet 14 is positioned adjacent an edgeof the device 150.

FIG. 22 illustrates a circular fluid delivery device 160 wherein aplurality of seams 130 radiate outwardly from approximately a centerpoint of the device 160. The fluid inlet 14 may be positioned adjacentan edge of the device 160, as shown in solid line, or alternatively maybe centrally positioned, as shown in phantom.

Although preferred embodiments of the invention have been described indetail, certain variations and modifications will be apparent to thoseskilled in the art, including embodiments that do not necessarilyprovide all of the features and benefits described herein. That is, someembodiments may exemplify one or more features or benefits, while otherembodiments exemplify other features or benefits. Accordingly, the scopeof the invention is not to be limited by the illustrations or theforegoing descriptions thereof, but by the claims that follow.

1. A fluid medication delivery device, comprising: a fluid impermeablepouch having first and second opposing walls, the first wall and thesecond wall defining a space therebetween, the space defining a fluidreservoir of the delivery device, the second wall including a pluralityof openings therethrough defining a diffusion area of the deliverydevice; a coiled wire member covering at least the diffusion area of thedelivery device, the coiled wire member comprising a plurality ofadjacent wire sections defining a plurality of gaps therebetween, thecoiled wire member being configured such that fluid within the fluidreservoir must pass through the coiled wire member before exiting thedelivery device.
 2. The fluid delivery device of claim 1, wherein thecoiled wire member comprises a single wire element extending in asubstantially consistently increasing radius from a first end to asecond end of the wire element to form a coiled shape.
 3. The fluiddelivery device of claim 1, wherein the coiled wire member issubstantially planar.
 4. The fluid delivery device of claim 1, wherein aperipheral edge of the coiled wire member is secured to the second wallof the fluid impermeable pouch.
 5. The delivery device of claim 1,wherein the fluid medication delivery device further comprises a fluidinlet.
 6. The delivery device of claim 5, wherein the fluid inletcomprises a one-way valve configured to permit fluid to enter the fluidreservoir and to prevent fluid from exiting the fluid reservoir throughthe fluid inlet.
 7. The delivery device of claim 1, wherein the fluidimpermeable pouch comprises at least one internal wall within the fluidreservoir, the internal wall segmenting the fluid reservoir intomultiple regions interconnected with one another.
 8. The delivery deviceof claim 7, wherein the at least one internal wall is defined by a sealbetween the first and second opposing walls.
 9. The delivery device ofclaim 1, wherein a fluid is diffusable through the plurality of openingsin response to a pressure imparted on the fluid by an external source offluid pressure.
 10. The delivery device of claim 1, wherein the pouchcomprises a circumferential seal between the first and second opposingwalls.
 11. The fluid delivery device of claim 1, further comprising apump configured to apply a pressure to a fluid, the pump beingconnectable to fluid impermeable pouch to supply a flow of the fluid tothe fluid reservoir during a delivery cycle.
 12. The fluid deliverydevice of claim 11, wherein, when the pump is connected to the fluidimpermeable pouch, the fluid within the reservoir is diffusable throughthe plurality of openings in response to the pressure applied by thepump.
 13. The delivery device of claim 1, wherein the fluid impermeablepouch comprises a material selected from one of polyethylene,polysulfone, polyethersulfone, polyvinylidene diflouride, polycarbonate,nylon, high density polyethylene, and polytetraflouroethylene.